Don't throw away the stack trace when tests fail

Don't throw away the stack trace when tests fail

Most unexpected exceptions are completely useless yielding message
like "null" or "3" or in the best cases something reasonable, but
still out of context.

Just declare the test as throwing an exception. That will retain
the full stack trace leading to the point of failure without using
a debugger or changing the code.

Change-Id: Id2454d328d1aa665606ae002de2c3805fe7baa8e